der Messenger
messenger
A software application or online service for exchanging instant messages.
Schick mir die Adresse bitte per Messenger, nicht per E-Mail.
Please send me the address by messenger, not by email.

messenger
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messenger
A software application or online service for exchanging instant messages.
Schick mir die Adresse bitte per Messenger, nicht per E-Mail.
Please send me the address by messenger, not by email.

'Messenger' is a word from English that is firmly established in German. It is pronounced as in English and almost always refers to an app for instant messages.
Welchen Messenger benutzt du am liebsten?
Which messenger do you like using best?
When referring to the app, the preposition 'per' (by/via) or 'über' (through/via) is often used. Typical phrases are 'per Messenger schicken' (to send by messenger), 'über den Messenger schreiben' (to write via the messenger), or 'eine Nachricht im Messenger bekommen' (to get a message in the messenger).
Ich schicke dir die Fotos später über den Messenger.
I'll send you the photos later via the messenger.
The meaning 'Bote' (messenger) or 'Kurier' (courier) is extremely rare in German. You will almost only hear or read it when people are talking about the English-speaking world, for example about bike couriers in U.S. cities.
In dem Film arbeitet die Hauptfigur als Messenger in New York.
In the film, the main character works as a messenger in New York.
chat
'der Chat' and 'der Messenger' both belong to digital communication. 'Chat' mainly means the conversation itself, that is, the messages you write with one or more people. It can also mean the area in an app where messages are written. 'Messenger' more often means the app or service used to send such messages. Learners may confuse the words because you chat in a messenger. As a simple rule: the messenger is the tool; the chat is usually the conversation.

Für die Gruppe benutzen wir einen sicheren Messenger.
We use a secure messenger for the group.
Im Chat schreibt mir Tom, dass er später kommt.
In the chat, Tom writes to me that he is coming later.